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United States Patent |
5,178,680
|
Tenney
,   et al.
|
January 12, 1993
|
Fire retardant delivery system
Abstract
A delivery system for delivering liquid fire retardant material to cotton
batting during the course of producing the cotton batting includes a spray
manifold arrangement including a liquid conduit carrying the fire
retardant material under pressure, a parallel air manifold carrying air
under pressure and a plurality of spaced nozzles distributed across the
mainfold, each of which is connected to both conduits. This manifold is
physically positioned in the cotton batt producing machines just
downstream of the garnetting rollers where two separate thin webs of
cotton are produced. These webs are impacted by spray from the nozzles
just ahead of and at the point where the webs are combined. A tank
containing the fire retardant material is connected to a regulated source
of air under pressure some of which is supplied to put the contents of the
tank under pressure such that it flows to the liquid conduit and some of
which is supplied to the air manifold.
Inventors:
|
Tenney; Diane (Whittier, CA);
Dosdourian; Michael (Whittier, CA)
|
Assignee:
|
Tri-Spray Systems Corporation (Whittier, CA)
|
Appl. No.:
|
671018 |
Filed:
|
March 18, 1991 |
Current U.S. Class: |
118/315; 118/325; 156/62.8; 156/550 |
Intern'l Class: |
B05C 005/00 |
Field of Search: |
118/315,325
156/62.8,550,551
|
References Cited
U.S. Patent Documents
3219276 | Nov., 1965 | Norris | 118/315.
|
Primary Examiner: Jones; W. Gary
Assistant Examiner: Friedman; Charles K.
Attorney, Agent or Firm: Wagner & Middlebrook
Claims
What is claimed is:
1. In combination with a batt making machine including a hopper containing
organic cellulose material, means distributing said material into at least
a pair of thin webs, means for advancing the webs in converging generally
triangular paths and thereby combining said webs into a double thick web
and conveyor means carrying said combined webs from said combining means
to form batts;
the improvement characterized by a system for applying liquid fire
retardant material to said webs comprising air and liquid conduits
positioned between said web as they converge, a plurality of spray nozzles
distributed along said conduits, each of which is connected to both said
air and liquid conduits, said nozzles being located within said combining
means and directed toward said webs at the point in said triangular path
where said webs converge;
means connecting a source of fire retardant liquid under pressure to said
liquid conduit;
means connecting a source of air under pressure to said conduit; and
pressure regulator means connected to regulate the pressure of liquid and
air to said nozzles such that an atomized spray of air and fire retardant
material is directed to impregnate said webs just ahead of the point where
said webs are combined in said combining means and to permeate each of the
webs without destroying their web form.
2. A system for applying liquid fire retardant material as claimed in claim
1 wherein said source of liquid fire retardant material comprises a tank
containing said material and said source of air under pressure is
connected to said tank to cause said liquid fire retardant material to
flow to said liquid conduit and wherein said liquid and air conduits
extend across the width of said webs whereby said nozzles apply fire
retardant to the full width of both webs simultaneously.
3. In a cotton batt making machine including hopper means containing
cotton, garnetting means for distributing said cotton into at least a pair
of continuous, wide, thin webs, means for combining said webs into a
thicker web for forming into batts and conveyor means carrying said webs
to said combining means;
the improvements comprising:
a system for applying liquid fire retardant material to said webs
comprising air and liquid conduits positioned between said webs, a
plurality of spray nozzles distributed along said conduits, each of which
is connected to both said air and liquid conduits, said nozzles being
directed toward the adjacent surfaces of said webs just before the webs
reach said combining means;
means connecting a source of fire retardant liquid under pressure to said
liquid conduit;
means connecting a source of air under pressure to said air conduit; and
pressure regulator means connected to regulate the pressure of liquid and
air to said nozzles such that an atomized spray of air and fire retardant
material is directed across the width of said webs just ahead of the point
where said webs are combined in said combining means.
4. A system for applying liquid fire retardant material as claimed in claim
3 wherein said source of liquid fire retardant material comprises a tank
containing said material and said source of air under pressure is
connected to said tank to cause said liquid fire retardant material to
flow to said liquid conduit;
and where said air pressure is applied in the order of 16 psig and fire
retardant is maintained at in the order of 5 psig to deliver fire
retardant to substantially permeate the webs with fire retardant without
destruction thereof.
5. In a cotton batt making machine including hopper means containing
cotton, a garnett machine including at least two garnett rollers, conveyor
means for conveying cotton to said hopper and from said hopper to said
garnett machine, and a delivery system for combining the webs of cotton
from each of said two garnett rollers;
a system for applying liquid fire retardant material to said webs
comprising elongated air and liquid conduits positioned between said webs
extending substantially the width thereof, a plurality of spray nozzles
distributed along said conduits and connected thereto said nozzles being
directed in the direction of travel of said webs toward the junction where
said webs are combined, means connecting a source of fire retardant liquid
under pressure to said liquid conduit, means connecting a source of air
under pressure to said air conduit, pressure regulator means connected to
regulate the pressure of liquid and air to said nozzles such that an
atomized spray of fire retardant material is directed to said webs to
permeate said webs without destruction thereof just prior to the combining
of said webs.
Description
BACKGROUND OF THE INVENTION
This invention relates to a system and process for applying or delivering
liquid fire retardant material to cotton batts, cotton insulation and the
like during course of the production.
The production of cotton batts is an old and well known process using
machinery which in general has long been in the public domain. At least
several hundred companies throughout the United States produce cotton
batts for use in making furniture or mattresses, or for insulation, or for
other purposes. For the most part, the basic processes are essentially the
same, as described below, although some installations may vary such as to
the nature and type of equipment for dust abatement, or conveyors etc. The
basic production machinery includes a picker which receives chunks or
slabs of compressed raw cotton manually pulled from the bale and put on a
feed table feeding the picker. The picker includes a large roller having a
number of long spikes which tear the slabs of cotton into smaller pieces.
A fine mist of light oil is typically added at this point. These pieces
are then transferred to a large housing or hopper containing a conveyor
which includes smaller spikes and which further blends and fluffs up the
cotton. From this hopper/conveyor called a willow, the cotton is sent to a
garnetting machine which includes a significant number of rollers having
external spikes and which break the cotton down into finer segments and
segregate it into two thin wide webs which are delivered from the last
rolls in the garnetting machine called comber rolls. These webs which may
be as thin as 1/16 to 1/2 inch are then combined by being conveyed
together to provide a double thickness and this double thick layer is then
supplied to a lapper conveyor which doubles the layers back and forth,
thereby stacking the layers to form a web of the desired thickness. This
web is then run through a feed conveyor to a roller to compress the batts
as desired before they are cut to desired lengths.
Such cotton batts are, of course, very flammable and there are various
requirements that they be treated with some form of fire retardant
material. For many years the standard method of making the cotton batts
fire retardant has been to apply a fine spray of very light oil to the
cotton, usually at the picker. Boric acid powder is then shaken on the
cotton web, usually upstream of the lapper conveyor. The fine oil serves
both as a dust abatement measure and as a means to cause the boric acid
powder to stick to the cotton. This process, although effective, leaves
much to be desired because of the need to supply substantial quantities of
the oil and boric acid powder; because the boric acid powder tends to
create a dust problem despite the use of the oil; and because the boric
acid powder is somewhat hazardous to the workers nearby, both because of
adverse effects from breathing it and because it becomes very slippery
underfoot. It has also been found that the boric acid powder tends to
shake out of the cotton batt material after an extended period of time.
Applicants have been aware of the availability of fire retardant materials
in liquid form which have been usefully employed in a number of
applications where porous or cellulose-type materials are involved. In
particular, it has been found to be useful for retarding the spreading of
fire in natural fiber materials such as straw, paper and various forms of
wood such as plywood, wood shakes or framing lumber. One such liquid fire
retardant material is marketed by Nochar, 8101 Crawfordville Road,
Indianapolis, Ind. 46253. This material is non-toxic and biodegradable,
absorbs into the fibers of the above listed natural fiber materials and
does not dry out or separate from the protected material.
In contacting several cotton batting manufacturers, applicants were made
aware of the process and equipment described above and the several
disadvantages inherent in the application of boric acid powder to the
cotton. Testing by applicants of the liquid fire retardant material on the
cotton batting demonstrated that the retardant material was effective to
reduce the flammability of the cotton material to the level required by
the State of California Department of Consumer Affairs Technical Bulletins
Nos. 116 and 117. One test specified by this document, which must be
complied with to sell cotton batting in furniture or mattresses in
California, is that a lighted cigarette placed on the cotton batting
material, must not burn or char the cotton more than an inch around the
cigarette in any direction. Applicants found that there was no known
system for applying a liquid fire retardant material such as that
described above to the cotton batting material.
BRIEF DESCRIPTION OF THE INVENTION
Applicants initially devised a manifold structure which was dimensioned to
reach across the width of the conveyors used in the above process, the
manifold structure including an air conduit, a liquid conduit and a series
of spray nozzles connected to the air and liquid conduits for distributing
a spray of liquid fire retardant material across the web of cotton moving
along the conveyors. A tank connected to an available supply of air under
D pressure was filled with the liquid fire retardant material and supplied
with air under pressure to force the liquid to flow to the liquid conduit
part of the manifold structure. The air source, regulated to the desired
pressure was supplied to the air conduit part of the manifold.
The manifold was first connected to direct spray at the cotton in the
picker. To get adequate penetration, the cotton was made excessively wet
which interfered with subsequent processing. It was then attempted to
locate the spray manifold downstream of the point where the thin webs from
the garnetting machine were o combined. Despite a substantial amount of
experimentation with air and liquid pressure levels, the penetration
proved inadequate to provide an acceptable level of fire retardancy.
Applicants then placed the air and liquid spray manifold just downstream of
the final garnetting rollers or combers and directed the spray at the thin
webs from these rollers just ahead of and at the point of combining the
thin webs. After a certain amount of experimentation with liquid and air
pressure levels and with some different types of spray heads, a system and
process was perfected which provided excellent fire retardant qualities in
the cotton, did not excessively wet the cotton, and which resulted in a
substantial reduction in the overall amount of fire retardant material
used.
BRIEF DESCRIPTION OF THE DRAWING
This invention may be more clearly understood from the following detailed
description and by reference to the drawing in which:
FIG. 1 is a schematic drawing of a production line for manufacturing cotton
batting material with our fire retardant delivery system installed;
FIG. 2 is a schematic diagram of the air and liquid manifold system used in
the fire retardant delivery system of FIG. 1;
FIG. 3 is an enlarged view of a portion of the production line showing our
fire retardant delivery system installed; and
FIG. 4 is a perspective drawing of the tank employed in our fire retardant
delivery system including conduits and regulators.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a somewhat simplified schematic drawing of a
production line for manufacturing cotton batting material is shown. The
compressed cotton pulled in clumps from the bale 10 is manually placed on
a feed table 12 which delivers it to a large container 14 called a picker
which has a rounded top and which carries internally a rotating shaft
having a substantial number of long spikes. This is the point where a fine
mist of light oil was added in the prior art process and this step may be
retained as a dust abatement measure if other dust abatement equipment is
not adequate or present. The clumps of cotton are reduced in size
substantially in the picker and are then supplied through a conveyor 16 to
a large hopper 18 called a willow. In this hopper is an endless belt
conveyor 20 which carries a large o number of spikes, finer then those of
the picker, which further break the cotton apart and fluff it up.
The cotton is then conveyed to a garnetting machine 22 consisting of a
large number of rollers each having relatively short spikes on its
surface. Passing through the garnetting machine 22, the cotton is broken
into much finer fragments and leaves the last pair of rollers, called the
comber rollers, in the form of a pair of upper and lower thin webs of
cotton 24 and 26, respectively, which may be approximately 1/16 to 1/2
inch thick. From the garnetting machine, the upper and lower webs 24,26
are combined in a lapper conveyor 28 which folds the combined webs over
and over to arrive at the desired batt thickness. The batts at the desired
thickness are then supplied to a feed conveyor 30, to a roller 32 which
compresses the batt somewhat and to a cutter 34 which cuts the batts to
the desired length.
Located just upstream of the location where the separate webs 24,26 from
the garnetting machine are combined such that it is physically positioned
between the webs, is a manifold structure including an air conduit 36 and
a liquid conduit 38 with a plurality (normally 6) of spray nozzles 40
distributed across the manifold, each of which is connected to the air and
liquid conduits. Depending upon the width of the webs, the number of spray
nozzles may vary. We have found a spacing of ten inches to be suitable for
the application described herein. Each of the air and liquid conduits is
connected to a suitable air and liquid hose, numerals 42 and 44
respectively, which are connected to pressure regulating means located on
the top of a tank 46 containing liquid fire retardant material and air
under pressure. Liquid conduit 38 and associated pipes and spray nozzles
are preferably formed of stainless steel since the liquid fire retardant
material is slightly corrosive to some metals. Because of the tendency of
bits of cotton to adhere to the conduits 36 and 38 and to build up on the
nozzles, it is useful, though not absolutely required, to shield conduits
36 and 38 and adjacent nozzle parts with polytetrafluroethylene material
(Teflon).
FIG. 2 is a schematic diagram of the air and liquid manifold system used in
our fire retardant delivery system. Shown in this view is the tank 46
which includes a fill pipe 56 through which the liquid fire retardant
material is supplied. A liquid outlet pipe 58 is threaded into the tank
and includes an internal delivery pipe reaching substantially to the
bottom of the tank 46. Air under substantial pressure is supplied to a
filter 60 and a regulator 64 carried on the tank which regulates the
pressure to a level compatible with the system, such as 15 psi. The
filtering function is necessary because many industrial air supply systems
also supply undesirable amounts of oil, dirt or lint which would tend to
clog the nozzles. Air from the filter 60 is connected through a pipe 62 to
a regulator 64 on the tank which permits air under regulated pressure to
enter the tank and thereby place its contents under sufficient pressure
that the fire retardant material will flow readily through hose 44 to
liquid conduit 38. The pressure in liquid conduit 38 is regulated by means
of a pressure regulator 64.
Air from the filter 60 is also supplied through hose 42 to air conduit 36
where its pressure is regulated by means of a pressure regulator 68.
Suitable pressure gauges 70, 71, 72 and 73 are preferably connected to air
and liquid conduits 36 and 38 respectively.
Applicants have found that with the air pressure in the air conduit 36 at
16 psig and the liquid pressure in conduit 38 maintained at 5 psi, our
fire retardant delivery system will spray 1.4 gallons of fire retardant
per hour on 350 lbs. of cotton batt material delivered through the
described production system.
FIG. 3 is an enlarged view of the portion of the production line where our
fire retardant delivery system is installed. Feeding from an upper
garnetting roller is a thin web of cotton 24 carried on an upper slide pan
48. Feeding from a lower garnetting roller is a second thin web of cotton
26 which is carried upwardly at an angle by a conveyor 50 which may form
part of the lapper conveyor 28. As the upper batt 24 feeds from the slide
pan 48 it is laid on top of the second web 26 travelling along conveyor
50. Prior to combining of webs 24 and 26, the webs may be as thin as 1/16
inch thick and approximately 60 inches wide.
Physically positioned between slide pan 48 and the conveyor 50 is shown, in
section, upper air conduit 36 and a lower liquid conduit 38 each connected
to a spray nozzle 40. A pipe nipple 52 is connected between the air
conduit 36 and spray nozzle 40 and a pipe nipple 54 for conveying liquid
spray retardant material is connected between liquid conduit 38 and spray
nozzle 40. Spray nozzles 40 may preferably be of the type providing
automatic shut-off when the air pressure is shut off which would prevent
liquid fire retardant material in the manifold 38 from continuing to flow
or "dribble" on to the lower web 26.
FIG. 4 is a perspective drawing of the tank employed in our fire retardant
delivery system including specific arrangements of conduits and
regulators. The tank 46 is connected to a source of air under pressure
supplied through a hose 59 which air is filtered through filter 60 after
which it is supplied through pipe 62 to a first regulator 64 which
controls the pressure of air supplied to the tank. Liquid fire retardant
material is placed in tank 46 through filler pipe 56 and is put under a
positive air pressure to cause it to feed out of a check valve 58 to hose
44. Air from filter 60 is also supplied to a regulator 68 which controls
the air pressure in conduit 36 supplied through hose 42. A pressure relief
valve 65 and a manually operated bleed valve 66 are also installed on the
tank 46.
It will be recognized that, as compared with the currently used system of
supplying oil and boric acid powder to make the cotton batting material
acceptably fire retardant, applicants' system has a number of advantages.
A much smaller quantity of material is used. The liquid fire retardant
material is biodegradable and non-toxic when used as described and when
sprayed as described, lands on and is absorbed into the cotton fiber with
little residue either in the air or on the floor. This contrasts o with
the boric acid powder which is present in the air and on the floor in
quantities sufficient to require workers to wear masks when working near
the point of application. The liquid fire retardant material is retained
in the cotton fiber indefinitely and does not shake out after one or two
years as does the boric acid powder. The quantities of liquid fire
retardant used are such that treating a given amount of cotton is
significantly less expensive than when using the described oil and boric
acid process.
The fire retardant qualities remain effective irrespective of the thickness
of the ultimate batts so long as the spray is applied to the thin webs as
desired. Much thicker layers of cotton may be used for insulation than for
furniture or mattresses and the fire retardant is essentially uniform
throughout the material. Our system is also capable of applying the liquid
fire retardant to other organic, cellulose-type material such as shredded
paper so long as it can be fed in thin webs past the spray manifold as
described.
The above described embodiment of the present invention is merely
descriptive of its principles and is not to be considered limiting. The
scope of the present invention instead shall be determined from the scope
of the following claims including their equivalents.
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